The periodic table, also called the periodic table of elements, is an organized arrangement of the 118 known chemical elements. The chemical elements are arranged from left to right and top to bottom ...

One hundred fifty years after Russian chemist Dmitri Mendeleev published his system for neatly arranging the elements, the periodic table it gave birth to hangs in every chemistry classroom in the ...

Recognize these rows and columns? You may remember a detail or two about this mighty table’s organization from a long-ago chemistry class. Elements are ordered according to their number of protons, or ...

On the periodic table, most elements have at least one stable form. But others have only unstable forms, all of which decay by emitting radiation and transforming into different elements until ...